This study will investigate the feasibility, safety, acceptability, and preliminary efficacy of a brief, group intervention designed to prevent perinatal depression (PD). We will develop and evaluate a behavioral preventive intervention based on Mindfulness-Based Cognitive Therapy (MBCT), which has been found to significantly reduce rates of relapse of recurrent depression among general adult samples and has high relevance to the prevention of PD. MBCT is non-pharmacological, offers an alternative to traditional one-on-one care models, and is based on a clear conceptual and empirical relationship between the specific intervention strategies and the most robust risk factor for perinatal depression, namely depressive history. The project will involve 3 phases, implemented in 2 obstetric settings: 1) conceptualizing the intervention based on theory and empirical research (MBCT for perinatal depression; MBCT-PD), 2) developing and standardizing MBCT-PD, and 3) pilot testing its efficacy in preventing relapse and recurrence among perinatal women with histories of depression. Phase 1 work is already under way. In Phase 2, we propose an open-trial to develop the MBCT-PD program (N=20). Based on an iterative process, we will finalize a participant- and expert informed manual for MBCT-PD that is sensitive and specific to the developmental factors associated with PD. In Phase 3, we propose to test MBCT-PD in a pilot randomized controlled trial comparing MBCT-PD to Treatment-as-Usual (TAU) (N=160). We will test the primary hypothesis that participants receiving MBCT-PD will experience improved depressive outcomes compared to participants receiving TAU, including testing group differences in rates of relapse/recurrence and exploring group differences in depressive symptom severity. We will also explore group differences in secondary outcomes, including anxiety and stress and obstetrical complications, and will explore potential moderators and mediators of depression outcomes. Finally, we will train and evaluate the ability of behavioral health care providers to administer the MBCT-PD program with fidelity. Given the negative and enduring consequences of untreated perinatal depression for women and their children, low rates of treatment seeking, and concerns associated with pharmacological approaches, the development and ongoing investigation of MBCT-PD may have significant benefits for women, children, and society at large [unreadable] [unreadable] [unreadable]